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Smoke on new motor startup, normal?


Guest 73Turbo240z

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Guest 73Turbo240z

Alright we fired up my L28ET today, running on MSnS-E now...

 

I don't have room for the stock PCV system w/ this HY35w turbo setup, so i used the PCV tube w/ a K&N breather on it, and then another breather on the valve cover...

 

When we started it up today whafts of vapor/smoke came from the PCV breather... nothing from the VC breather.

 

We were guessing that it was assembly lube burning off the rod's/pistons/crank/etc... but i figured i'd ask just to be safe, anyone have incite to this?

 

Also i couldn't ID this intake manifold, i'm getting a unusually high idle of 1300ish on average, we corked every visible opening in the manifold, and unplugged the throttle buttlerfly rod so it was 100% closed w/ out a doubt... still producing a 1300ish rpm idle.

 

The previous owner cut the EGR off, and we were guessing there might be pinhole entrances into the manifold runners or somthing like that, but i couldn't see anything... so figured i might get some insite from you guys on if there are holes aside from the ones i've seen.

 

Pics will be up in a little bit.

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Guest 73Turbo240z

Everything is corked on the top side of the manifold (not pictured)

 

Your seeing the underside, the PCV valve you see is now corked w/ the proper thread bolt and some sealant.

 

That leaves just that rectangular channel you see... best as i can tell, it has those 6 holes in it, and it has the ends each open as you can see...

 

The only place i can guess there would be holes aside from that is pinholes in each runner inside the rectangle boxing? Or does anyone know if those mount areas for the factory heat shield go all the way through? cause i don't believe i've checked those either.

 

Only thing i can think to do at this point is try to open the throttle plate and get my mag light off in there... start looking for a light source.

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Propane torch for any vacuum leaks, it's the simplest and easiest way... although, you said you unhooked the throttle linkage so it's all the way closed, but IIRC you are using a 60mm 240sx TB, correct? it has it's own idle set screw, which prolly needs adjusted and when installed on an L intake manifold it ends up being really hard to adjust, or even see, it's opposite the TPS, underneath the manifold kinda, a real pain to adjust. You probably already thought of this though, I just thought I would throw it out there. I think it would take a pretty major vacuum leak to make the idle 1300, if the throttle plate where 100% closed, with it 100% closed the engine should die at idle. You want to chase down any vacuum leaks anyway, as they will become boost leaks once you spool up that big turbo!

 

as for smoke, you mentioned some out of the crankcase breather, a little out of here is fairly normal with a fresh engine (rings not quite seated) and will prolly go away, a LOT would cause concern, you did stagger the compression rings, and installed the oil ring helper springs correctly, right? I have screwed up the oil springs before, and had tons of smoke, out the tailpipe though, not the breather...

 

Good luck and have fun tuning!!!

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Guest 73Turbo240z

From what i found in the little time i had tonight....

 

1. leak @ the 60mm TB spacer... fixed that, idle went to 1100ish...

 

2. leak @ 2 injector to manifold areas, gotta redo the fuel rail to get those supra 440cc's in there a bit more snug....

 

 

so yea, no opennings in that channel just as i figured, now i just have to get the brakes/clutch bled, do final torquing on the rear diff to halfshaft nuts, and bolt on some wheels/seats and she'll be pilotable.

 

if anyone out there has a 240z w/ stock fuel tank in it, i'd really like to know the color/placement of wiring on your fuel sender... can't seem to remember on mine, and i went through all the hassle of sumping a stock tank so i could use the factory gauge.

 

Looks like a 3 wire affair, black assumed ground, dunno which or where the other 2 go.

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told ya about the t-body spacer and the intake manifold.. damn im good!

call me tomorrow.... ill stop on by after my date.. yes i said date.. NO WAY!

 

mike

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Guest 73Turbo240z
told ya about the t-body spacer and the intake manifold.. damn im good!

call me tomorrow.... ill stop on by after my date.. yes i said date.. NO WAY!

 

mike

 

uhh.. bring her by the garage playboy... give her a sneak peak at what yours would be like... it'll be your "in" for sure...

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Guest DanielB1987
lol im sure she would just love hanging around smelly old cars and abunch of guys talking about GN's and Z's... lol

 

mike

 

who wouldn't??? But anyways. A stock 240sx TB is a 60mm? S13 or S14? And does it bolt right up?

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Guest 73Turbo240z

i've started it up probally half a dozen times now... still smokes out of the crankcase, i'm going to see what happens after i've driven it some and really wrapped out the RPM's a bit... see if that helps, cause from my logic, it's either startup grease burning off, or it's blowby from the pistons cooking the oil... one being normal, the other being very bad, especially for a brand new engine...

 

that sound about right?

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